Blank-holding means for sheet-metal presses



y 21, 1929- .1. NELSON 1,714,315

BLANK HOLDING MEANS FOR SHEET METAL PRESSES Filed Nov. e, 1926 2 Sheets-Sheet 1 J. NELSON May 21, 1929. v

BLANK HOLDING MEANS FOR SHEET METAL PRESSES Filed Nov. 6, 1926 2 Sheets-Sheet 2 :14) Figure 2 is a Patented May 21, 1929. v

UNITED STATES PATENT OFFICE.

JOHN NELSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO MARQUETTE TOOL & MANUFAC- TUBING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

BLANK-HOLDING MEANS FOR. SHEET-METAL PRESSES.

Application filed November 6, 1926. Serial No. 146,629.

This invention'relates to improvements in blank holding means for sheet metal drawing presses, and one of the objects of the invention is to provide improved means whereby a substantially uniform or unvarying pressure will be provided throughout substantially the entire length of the stroke of the press, and which means will also eliminate back lash.

A further object is to provide improved means for returning the pin or pressure plate to restore the draw ring or blank holding member to its initial or starting position. To the attainment of these ends and the accomplishment of other new and useful objects as will appear, the invention consists in the features of novelty in substantially the construction, combination and arrangement of the several parts hereinafter more fully described and claimed and shown in the accompanying drawings illustrating this invention and in which,

Figure 1 is a front elevation of a portion of a press showing a blank holding means 2 const-ructedin' accordance with the principles of this invention, applied thereto, the blank holding means and portionsof the press being in section, the press being shown in its starting position.

view similar to Figure 1,

showing the parts in another position.

Figure 3 is a detail sectional view taken on line 3-3, Figure 2.

Figure 4 is a detail sectional view taken on line 4- Figure 2.

Referring more particularly to the drawings the numeral 10 designates generally the body of a press upon which is mounted a bed plate 11 which supports a die 12', with which 10 another die 13'connected with the ram or slide 14 cooperates. cable in the guideways by means of a link 15 connected with a crank shaft 16, the lat ler being rotated in any suitable manner.

All the above referred to parts may be of the ordinary and well known construction.

Co-operating with the die 12 and encompassing the same is a draw ring or blank holding member 17, which is supported by the usual pins 18 which pass through the bed The ram 14 is recipro-' plate 11 and engage and rest upon a pin or pressure plate 19 below the bed plate 11.

Supported below the bed plate at any suitable distance and-by means of suspension or hanger rods 20, is a cylinder 21, which is preferably open at its top, the cylinder bemg provided with a circumferential flange or lugs 22, through which the ends of the 1 rods 20 pass. The cylinder is supported by these. rods preferably by means of nuts 23 which are threaded upon the ends 'of the rods and the nuts co-operate preferably with shoulders .24 on the rods 20 for holding the cylinder 21 in position. Reciprocable in the cylinder 21 is a piston 25 which has an opening theret-hrough forming a valve seat 26..

The piston is connected with the pin plate 19 to reciprocate therewith preferably by means of bars or rods 27 so that when the pin plate 19 is depressed the piston 25 will bellowered in the cylinder 21.

Within the cylinder 21 and normally'beneath the piston 25 is a liquid 28 which is non-compressible. necessary, be provided with packing 29.

Interposed between the pin plate 19 and the flange orlugs 22 011 the cylinder 21, is a resilient member 30, preferably in the form of a coil spring, one end of which e'ngages the pin plate and the other end engages and The piston 25 may, if

rests upon the lugs or flange 22, being coiled about the upper part of the cylinder 21. This resilient member 30 tends normally to hold the pin or pressure plate 19 against the bottom of the bed plate 11 or in a position to support the blank holding member or draw ring 17 so that the upper face will normally which co-operates with the valve seat 26 in the. piston to close the opening through the piston.

The valve is held to its seat in the piston 25 under normal conditions by means of a spring 34', preferably a coil spring, one

through the bottom of the cylinder.

The piston 25 is provided with an additional opening 38 which is closed by a valve 39 opening ina direction opposite to the direction in which the valve 33 opens. The valve 39 is normally held seated by means of a spring 40, the valve 39 operating -when the piston 25 is loweredin the cylinder 21 against the liquid 28 therein, to close the opening 38, and when the piston 25 iselevated, the valve 39 will be opened by suction created in the cylinder 21 beneath the piston 25.

This valve 39 is provided so as to permit the liquid, which passes through the opening in the piston 25, when the valve-33 is unseated, to return to the bottom side of the piston when the valve 33 is seated and on the upstroke of the piston 25.

The extension 31 on the piston 25 is provided with ports or openings 41, which form communication between the cylinder 21 and a chamber 42, beneath the valve 33, so that when the piston 25 is lowered against the liquid in the cylinder 21 beneath the piston, the liquid will flow through the openings 41 into the chamber 42 so as to act upon the lower face of the valve 33 to unseat the latter. These ports 41 may be of any desired size, but the smaller .the ports are the weaker the spring or resilient member 34 may be to procure .the'same resistance. The valve stem 32 projects through and for a considerable distance beyond the extremity of the extension 31 and is provided with "a threaded extremity 43 upon which a nut 44 is threaded. A spring 45 encompasses the valve stem 32 between the end of the extension 31 and the nut 44 and operates upon the valve 33 to yieldingly hold the.

. valve against its seat 26. If desired, a lock nut 46 may be provided on the valve stem.

From this construction it will bemanifest that as the pin plate 19 is depressed the pressure of the resilient member or spring 30 will be increased while the pressure of the spring or resilient member 34 will be decreased. Therefore, the springs 30 and 34 must equalize each other and maintainthe member 17 substantially constant. That is, the springs must be in the same-relative -proportion of pressure at all times.

By adjusting the nut 44 upon the valve.

stem 32 the stress of the spring 45 may be varied and in this manner the degree of pressure upon the liquid 28 in the cylinder 21 which is necessary to unseat the valve 33,

may be controlled at will,

In operation and when the ram 14 descends and engages the blank or work 47, the blank will be gripped between the draw ring or 'blank holding member 17 and the die 13.

the cylinder and the piston will carry with it'the valve 33, causing the spring 34 to be weaker while the stress of the spring 30 becomes stronger. The spring 34 in conjunction with the resistance'liquid pressure will then equalize the spring 30.

As the'piston descends against the noncompressible liquid 28 in the cylinder 21, the liquid will be forced through the ports 41 against the valve 33 to unseat the latter against the stress of the springs 34 and 45, the liquid escaping to'the top side of the piston 25 within the cylinder 21.

The portion of the cylinder above the piston serves as a trap to catch the overflow of liquid.

When the piston 25 is at the bottom of its stroke and the ram ascends the spring 30 will return the pin plate 19 and draw ring 17 to their normal or initial positions. The draw ring or blank holding member 17 will follow the die 13 and the spring 30 maintains the draw ring or blank holding member 17 in contact with the die.13.

When the piston 25 returns or is elevated a vacuum will be created under the piston in the cylinder 21, which operates to suck the valve 39 open, thereby allowing the liquid on the top side of the piston 25 to run back into the cylinder beneath the piston.

The spring 40 is only suflticient in strength to maintain the valve 39 seated so that gravity, vweight of the valve 39, and weight of the liquid on the top side of thepiston 25 will assist in opening the valve 39 when, the piston 25 is elevated.

The spring 45 is always maintained under a constant pressure and this pressure may be determined and set, according to the pressure which it may be desired or determine. is necessary to unseat the valve 33 and constitutes the entire means for regulating the pressure against which the pin plate 19 operates, because as stated, it regulates the amount of pressure required to displace or unseat the valve 33.

pressure on the draw ring or blank holding Upon thereturn' stroke of the press the pressure of the liquid or the resistance in the cylinder is overcome by the escape'of the liquid through the opening. in the piston. and the spring is the only force tending to return the piston and pin plate.

The springs 34 and 45 do not act to exert any return pressure.

The spring 34 has, on the contrary, a tendency to slightly retard the return of the pin plate in opposition to the action of the spring 34. The action of the spring 34 depends upon the size of the ports controlled by the valve 33. I

With this construction there will be maintained a substantially constant'or uniform pressure throughout substantially the entire stroke of the ram, and back lash will be prevented because of the two springs 30 and 34 working in opposition to each other. The liquid 28 in the cylinder 21 will cause a resistance to the operation of the pin plate but no back pressure to return the pin plate.

As the draw ring or blank holding member 17 returns it will operate as a stripper to remove the cup or form which has been shaped over the die 12.

While the preferred form of the invention has been herein shown and described, it is to: be'understood that various changes may be made in the details of construction and in the combination and arrangement of the several parts, within the scope of the claims, without departing from 'the spirit of this invention.

What is claimed as new is 1. A drawing press including a blank holder,means for resisting .the movement of said blank holder, said means embodying a resiliently yielding element reacting upon the blank holder, and fluid pressure means also yieldingly resisting the movement of the said blank holder, the said resilient ele-' ment also operating to return the blank holder after the drawing operation.

. 2. A drawing press including a blank holder, means for resisting themovement of said blank holder, said means embodying a resiliently yielding element reacting'upon the blank holder, fluid under pressure greater than atmospheric for also yieldingly resisting the movement of the said blank holder, the said resilient element also operating to return the blank holder after the drawing operation, and means for varying at will the said fluid pressure. p

3. drawing press including a blank holder, means-for resisting the'movement' of said blank holderand or maintaining a substantially unvarying pressure of the blank holder throughout substantially the entire stroke of the press, said means embodying a resiliently yielding element and fluid under pressure greater than atmospheric for'also yieldingly resisting the movement of the blank holder, and means for varying at will the pressure of one of the re sistance creating means.

4. A drawing press including a blank holder, and means for resisting the movement of said blank holder and for maintaining a substantially unvarying pressure of the blank holder throughout substantially the stroke of the press, said means embodying two independent and different types of means both operatingto yieldingly resist the movement of the said blank holder, one only of said means being operable to return the blank holder.

5. A drawing press including a blank holder, means for resisting the movement of said blank holder and for maintaining a substantially unvarying pressure of the blank holder throughout substantially the stroke of the press, said means embodying two independent and different types of means both operating directly upon the said blank holder for yieldingly resisting the movement thereof, one only of said means being operable to return the blank holder, and means for varying at will the pressure of the other of the said resistance creating means.

6. A drawing press including a blank holder, and means for resisting the movement of said blank holder and for maintaining a substantially unvarying pressure of the blank holder throughout substantially the stroke of the press, said means embodying a resiliently yielding element and fluid under pressuregreater than atmospheric and operating directly .upon the said blank holder for yieldingly resisting the movement thereof, said resilientlyyielding element being also operable to return the blank holder, and means for varying at will the said fluid pressure. 1

7. A drawing press including a blank holder, means for resisting the movement of said blank holder and for maintaining a substantially unvarying pressure of the blank holder throughout substantially the stroke of the press, said means embodying a resiliently yielding element and fluid pressure means both acting directly upon the said blank holder, means for counterbalancing the said resiliently yielding means, said resiliently yielding element being also operable to return the blank holder, and means for varying at will the said fluid pressure.

8. A drawing press including a blank holder, means for resisting the movement of said blank holder and for maintaining a substantially unvarying pressure of the blank holder throughout substantially the stroke of the press, said means embodying a resiliently yielding element and fluid pressure means both acting directly upon the said blank holder, resiliently yielding means operating in opposition to the first recited resiliently yielding means, said resiliently upon the blank holder, and resiliently yielding means operating in opposition to the first recited resiliently yielding means for controllingthe action of the said fluid pres sure means.

10. A drawing press including a blank holder, means for resisting the movement of the blank holder, said means embodying a resiliently yielding element and fluid pressure means both acting directly upon the blank holder, resiliently yielding means operating in opposition to the first recited resiliently yielding means for controlling the, action of the said fluid pressure means, and means for varying at will the said fluid pressure. i

11. A drawing press including a blank. holder, means for resisting the movementof the blank holder, said means embodying a resiliently yieldable element and fluid pressure means both acting directly upon the blank holder, said fluid pressure means embodying a cylinder-and pist'on movable relatively one with relation to the other, a valved passage" throughthe piston, and resiliently yielding means for controlling the operation of said valve with relation to the. piston. j

12; A drawing press including. a blank 1 holder, means for-resisting the movement of the blank holder, said means embodying a resiliently yieldable'element and fluid pressure means both acting directly upon the blank holder, said fluid pressure means embodying a cylinder and piston movable relatively one with relation to the other, a valved passage through the piston, and resiliently yielding means operating 1n opposition to the first reci'ted resiliently yielding meansfor controlling the operation of said valve with respect to the piston.

13. A drawing press including a blank holder, means for resisting the movement of the blank holder, said means embodying a resiliently yieldable element and fluid pressure means both acting directly upon the blank holder, said fluid pressure means embodying a cylinder 'andipiston movable relatively one with relation to the other, a valved passage through the piston, and resiliently yielding means for controlling the operation of said valve withrelation to the piston, the first recited resiliently yielding means only, operating to return the said blank holder.-

14. A. drawing press including a blank holder, meansfor resisting the movement of the blank holder, said means embodying a 15. A drawing press including a blank holder, means for resisting the movement of the blank holder, said means embodying a resiliently yielding element andfluid pressure means both operating directly upon the blank holder, said fluid pressure means which is stationary and the other being connected with the said blank holder for movement therewith, there being a passage through the piston for liquid, a valve for controlling said passage and against which valve the fluid under pressure acts to unseat the valve, and resiliently yielding means tending normally to seat the valve.

16. A drawing press including a :blank holder, means for resisting the movement 'of .the blank holder, said means embodying a resiliently yielding element and fluid pres sure means both operating directly upon the blank holder, said fluid pressure means embodying a cylinder and piston one of which is. stationary and the other being connected with the said blank holder for movement embodying a cylinder and piston one of therewith, there being a passage through the.

piston for liquid, a valve for controlling said passage and against which valve the fluid under pressure acts to unseat the valve, resiliently yielding means tending normally to seat the valve, the last recited resiliently yielding means operating in opposition tothe first recited resiliently yielding means, and means for varying at will the fluid pressure necessary to unseat said valve.

17. A drawing press including. a blank holder, means for resistingthe movement of the blankholder, said means embodying a resilient-1y yielding element and fluid pressure means both operating directly upon the blank holder, said fluid pressure means embodying a cylinder and piston one of which is stationary and the other being connected with the said blank holder for movement therewith, there being a passage through the piston for liquid, a valve for'controlling said passage and against which valve the fluid under pressure acts to unseat the valve, resiliently yielding means tending normally to seat thevalve, additional means foryieldingly seating and maintaining said valve seated, and means for varying at will the stress of the said addit onal means to va y the fluid pressure necessary to unseat said valve, the said additional means .ried entirely by the valve.

18. A drawing press including a blank holder and'means for resisting the movement of the blank holder sai means embeing carbodying a resiliently yielding element and fluid pressure means operating directly upon theblank holder, said fluid pressure means embodying a cylinder; and piston one of which is stationary, means connecting the other with the blank holder for movement;

therewith, there being a passage through the piston for fluid, a valve carried by the piston for closing said passage, resiliently yielding means independent of the piston and tending normally to seat the-valve, additional means carried by the piston and operating to yieldingly seat said valve, and means for varying at will the stress of the ,said additional means whereby the degree of fluid pressure necessary to unseat'said valve with respect to the, piston may be varied at will.

19.'A drawing press including a blank holder and means for resisting the move ment of.the blank holder, said means embodying a resiliently yielding element and fluid pressure means operating directly upon the blank holder, said fluid pressure means embodying a cylinder; and piston one of which "is stationary, means connecting the other with the blank holder for movement therewith, there being apassage through the piston for fluid, a valvecarried by the piston for closing said passage, resiliently yielding means independent of the piston'and tending normally to seat thee valve, additional means carried by the piston and operating to yieldingly seat said valve, means for varying at-w ill the stress of the said additional means whereby the de 'i'ee of fluid pressure necessary to unseat said valve with respect to the piston may be varied at Wlll, h the piston, and a valve for controlling the last recited passage.

20. A holder and means for resisting the movement of the blank holder, said means embodying a resiliently yielding element and fluid pressure means operating directly upon the blank holder, saidfluid pressure means embodying a cylinder and piston one of which is stationary, meansconnecting' the other with the blank holder for movement therewith, there being "a passage through the piston for fluid, 'a valve carried by the piston for closing said assage, res liently yielding means indepen ent of the piston and tending normally to seat the valve, ad-

ditional means carried bythe piston and operating to yieldingly seat said valve, means for varying at will the stress of the sa1d additional means whereby the degree of rawing press including-a blank fluid pressure necessary to unseat said valve with respect to the piston may be varied at vwill, an additional passage I through the piston for liquid to pass, and resiliently yielding means forcontrolling the last said valve, said valvesoperating in opposite directions with respect to each vother. 21. A drawing press including a blan holder and means for resisting the movement of the blank holder, said means embodying a resiliently yielding element and fluid pressure means both operable directly upon the blank holder, said fluid pressure means embodying a cylinder and piston one of which is stationary and the other connected with the blank holder for movement therewith, there being a passage through the piston, a valve for closing the passage, a

guide on the piston, a stem on the valve seating the. valve, means for varying the stress of the'last recited resiliently yielding element, and an additionalmesiliently yielding element independent of the valve and operating to seat the valve.

22. A drawilig press including a holder and -means for resistin ment of the blank holder, sai

blank the move means embodying a resiliently yielding element and fluid pressure means both operable directly upon the blank holder, said fluid pressure means embodying a cylinder and piston one of which is statlonary and the other connected with the blank holder for movement therewith, therebeinga passage through the piston, a valve for closing the passage, a guide on the piston, a stem on the valve passing through the guide and extending therebeyond, a resiliently yielding element disposed between the valve and stem for seating the valve, means for varying the stress of the last recited resiliently yielding element,and an additional resiliently yielding element independent of the valve and operating to seat the valve, the first and last recited resiliently yielding elements operating in Opposition to each other.

23. A drawing press including ablank holder and means for resistin the movement of the blank holder, said means embodying a resiliently yielding element and seating the valve, means for varying the stress of the last recited resiliently yielding element, an additional resiliently yielding element independent of the valve and operating to seat the valve, there being an additherewith, there being a passage through the piston, a valve for closing the passage,

a guide on the piston, a stem on the valve passing through the guide and extending therebeyond, a resiliently yielding element disposed between the valve and stem for seating the .valve, means for varying the stress of the last recited resiliently yielding element, an additional resiliently yielding element independent of the valve and, operating to seat the valve, there being an additional passage through the piston, and a resiliently yielding valve for controlling the last said passage, the said valves operating in opposition to each other. I

25. A drawing press including a blank holder and means for resisting the movement of the blank holder, said means .embodying a resiliently yielding element and a self-contained fluid pressure means both acting directly upon the blank holder, and resiliently yielding means operatin in opposition to the first recited resilient y yield ing means for controlling the action of the said fluid pressure means.

26. A drawing press including a blank holder and means for resistin the movement of the blank holder, sai means embodying a resiliently yielding element and a self-contained fluid pressure means both acting directly upon the blank holder, said fluid pressure means embodying a cylinder and piston relatively movable, said cylinder containing a predetermined supply of .fluid transferable back and forth to opposite sides of the piston, said fluid acting on one side of the piston to create a resistance pressure, means for transferring .the fluid to the other side of the piston, and means con-' trolled by the fluid pressure for controlling such transfer of the fluid. 27. A drawing press including a blank holder and means for resisting the movement of the blank holder, said means embodying a resiliently yielding element and a self-contained liquld ressure means both actin directly upon the blank holder, said liqui pressure means embodying a cylinder and piston relatively movable, said cylinder containing liquid acting on one side ofthe piston to create a resistance pressure, means for transferring the liquid to the other side of the piston, means controlled by the liquid pressure for controlling such transfer of the liquid, and additional means operating to automatically control the transfer-of the liquid back to the 'first recited side of the piston. 1 a

28. A drawing .press including a blank holder and means for resisting the moveself-contained fluid pressure means fluid pressure means embodying a cylinder for containing fluid, said fluid being transferable back and forth to opposite sides of ment of the blank holder, said means em-U bodying a resiliently yielding elementand a both acting directly upon the blank holder, said the piston, a valved passage for transfer- I ring the fluid from one side of the piston to the 0ther,'and means yieldingly seating the valve, said valve being ada ted to be unseated against the stress 0 ,means by fluid pressure.

29. A drawing LPIBSS including a blank holder and means for resisting the movement of the blank holder, said means embodying a resiliently yielding element "and a selfcontained fluid pressure means both acting directly upon the blank holder, said fluid pressure means embodying .a cylinder for containing fluid transferable back and forth to opposite sides of the piston, a valved passage for transferring the fluid from one side the last said of the piston to the other, means yieldingly seatliig-the valve, said valve being adapted to be unseated against the stress of the last said means by fluid pressure, and means whereby the sai valve may be varied at will.

30. A drawing press including a blank holder and means for resisting the movement of the blank holder,\said means embodying a resiliently yielding element and a self-contained. fluid pressure means both acting directly upon the blank holder, said fluid-pressure means embodying a cylinder,

,for containing fluidv transferable back and forth to opposite sides of the piston, a valved passage'for transferring the fluid from one side of the piston to the other, means yieldingly seating'the valve, said .valve being the fluid pressure necessary to open,

adapted to be unseated against the stress of the last said means by fluid pressure, and means operating automatically for transferring the fluid back to the first recited side of the piston.

31. A drawing press including. a blank holder and means for resisting the movement of the blank holder, said means embodying a resiliently yielding element and a self-contained liquid pressure means both.

acting directly upon the blank holder, said liqui pressure means embodying a cylinder for contalmng liquid, 9. valved passage for transferring the liquid from one side of the piston to the other, means yieldingly seating the valve, said valve being adapted to be unseated against the stress of the last said means by liquid pressure, and means operating automatically for transferring the liquid back to the first recited side of the piston, the last recited means embodying a passage through the piston and a spring controlled Valve for controlling the last said passage.

32. A drawing press including a blank holder, a resiliently yielding element reacting upon the blank holder for yieldingly resisting the movement thereof, and fluid under pressure greater than atmospheric against which the said blank holder also operates to be yieldingly resisted thereby, both said resiliently yielding element and the fluid pressure means being disposed on the same side of the work, the said resilient element also operating to return the blank holder after the drawing operation.

33. A drawing press including a blank holder, means for resisting the movement of said blank holder and for maintaining a substantially unvarying pressure of the blank holder throughout substantially the entire stroke of the press, said means embodying a resiliently yielding element and fluid under pressure greater than atmospheric for also yieldingly resisting the move ment of the blank holder and disposed on the same side of the Work as.the said element, and means for Varying at will the pressure of one of the resistance creating means.

34. A drawing press including a blank holder, and means for maintaining a substantially unvarying pressure of the blank holder throughout substantially the stroke of the press, said means embodying two independent and different types of means each acting directly upon said blank, holder for yieldlngly resisting the movement of the blank holder and both disposed on the same side of the work, one only of said -means being operable to return the blank holder. 35. A drawing press including a blank holder and means for resisting the movement of the blank holder, said means embodying a resiliently yielding element and a self-contained fluid pressure means both acting directly upon the blank holder for yieldlngly resisting the movement of the blank holder, and both disposed on the same side of the work, and resiliently yielding means operating in opposition to the first recited resiliently yielding means for controlling the action of the said fluid pressure means.

In testimony whereof I have signed in name to this specification, October, A. D. 1926.

' JOHN NELSON.

y on this 13th day of 

